Effect of four types of psychophysiological interventions (relaxation, physical exercise, and intensive light exposure before the test, increased mental involvement in the test task) on characteristics of vigilance performance and subjective feelings were examined in a standard laboratory setting. A laboratory vigilance test in extremely monotonous conditions comprised of an acoustic discriminatory task and simultaneously performed continuous visual task. Three 90 minute sessions were conducted during 6 morning hours of one day. A total of 118 student volunteers (47 males) were divided into five groups, one of which was a control group. Short relaxation treatment did not prevent the usual performance deterioration but improved the subjective tolerance of monotony. Twenty knee-bends before session II or III had no positive influence. Twenty minute exposure to 750 lx of white light delayed the increase in signal omissions during the following session. An additional mental task which added more reason and so provided extra stimulation to the monotonous test activity appeared to be the best prevention of detection failures and „minisleeps“.

        Key words: monotonous work, performance reliability, psychophysiological methods